Electrical products including terminals of wiring A and terminals of wiring B which are joined together via soldering are well known. Soldering joint for such electrical products is performed by heating to melt solder after the solder is disposed between the terminals. A reflow furnace is generally used for the heating.
Now, resin parts are used for products in many cases. It is not too much to say that there is no electrical product without including resin parts. In a case where a resin product is heated in reflow furnace (heating furnace), resin parts of the resin product may be damaged from the heating. To avoid this, it is required for the resin parts to have heat-resisting property. In other words, resin parts having low heat-resisting property (low melting point/low softening point) are not employed in the above mentioned case.
However, in some cases, resin parts having low melting point (softening point) are positively desired to be used in products. An example of such cases include a case where a sheet including wirings formed thereon is formed into a predetermined shape by thermoforming. In other words, a case involving thermoforming requires resin parts having low melting point (softening point/heat-resistant temperature). This is because high heat-resisting property (melting point/softening point) makes it difficult to perform thermoforming.